Method and means for generating helical vanes



July 17, 1934. L G SYM NS 1,966,530

METHOD AND MEANS FOR GENERATING HELICAL VANES Filed July 2, 1930 4 Sheets-Sheet l Z IN V ENTOR.

ATTOR E168.

July 17, 1934. G YM- Ng 1,966,530

METHOD AND MEANS FOR GENERATING HELIGAL VANES Filed July 2, 1930 4 Sheets-Sheet 2 ally EN T OR.

July 17, 1934. YM 1,966,530

METHOD AND MEANS FOR GENERATING HELICAL VANES Filed July 2, 1930 4 Sheets-Sheet 3 V {Wr 5 M (fiNg TOR.

July17, 1934. L. G. SYMONS METHOD AND MEANS FOR GENERATING HELICAL VANES Filed July 2 1930 A ONEY 4 Sheets-Shea}. 4

Patented July 17; 1934 HELICAL VANES 7 Loren G. Symons, Hollywood, Calif., assignor, by

mesne assignments, to Grademor Corp., Ltd., Los Angeles, Calif., a corporation of California Application July 2. i930, Serial No. 465,369

8 Claims. (Cl.'90 -4) This invention relates in generalto the production of screws or worms having helical vanes on the peripheries thereof, and more particularly to the production of a helically vaned impeller for pumps and the like, in which the helix of the screw are adapted to mesh with a rotating gate forming a closure or abutment for subdividing a pump cylinder into inlet and outlet portions.

Accordingly this invention comprehends the generation by the means and method shown herein of a vane or helix of such character; that it will uniformly engage the teeth on the rotating gate so as to form a positive seal or closure in the groove between the successive turns of the helix.

In the considerationof this invention it may be understood that a pump of the character mentioned embodies a cylinder with an inlet and outlet, an impeller with a peripheral helical vane 4 having one or more turns Which-is rotatable in the cylinden'and a gate which has an'axis off-set from the axis of. the impeller and disposed at right angles thereto with teeth formed on the gate which are uniformly spaced apart to correspond as to'theircircular pitch to the pitch of the vanes on the impeller. Thus the. gate .partakes of the form of a crown gear with the axis of the teeth paralleling the axis of the gate or gear and spaced apart and formed at their. adja cent edges so as to contact with the adjacent sides of the vanes on the impeller.

Thus the rotation of the impeller serves to tate the gate. I

. In this connection it is obvious that due to the .variable relation of the successive portions. of the vane on the impeller, said vane, or vanes. cannot be of uniform cross section thruout its length, because of the varying angles of the teeth relative to the vane. It is, therefore, an important object of this invention to provide. a mechanism in the form of a jig or the like which can be employed as an accessory to a milling machine or other suitable machine tool for moving the work relative to the tool, or vice versa, in a helix forming operation, so that the. movement of the work relative to the tool or the tool relative to the work will correspond exactly to the relative movement of the gate teeth relative to plastic mass, and the walls of the groove so formed would contact with the edges of the tooth as long as the plastic mass was rotated, and the PATENT OFFICE tooth would follow thru the groove and make close'contact with the walls thereof.

In order to accomplish'the above objectsof invention, I have provided anefiective, simple and satisfactory mechanism which I have clearly illustrated in the accompanying drawings, in which 1 Fig. 1 is a plan view of the assembled mechanism arranged forvoperative connection with a milling machine or other suitable machine tool. I

Fig. 2 is a plan of a suitable cutter for the pur,- pose of my invention. a j

Fig. 3 is a fragmentary section of the same on; line 33 of Fig. 2.

Fig; 4 is a perspective view. of one of the cutte teeth displaced from the cutter.

-Fig. 5 is a top plan view of a suitable pedestal or standard for operatively supporting the generating fixture during use.

, Fig. 6 is asectional elevation of the assembled mechanism on line 6-6 ofFig. 1. v 2 Fig. Tis a transverse sectional elevation of the same on line 7.-7 of Fig. 1. V V

' Fig. 8 is a perspective view of a worm capable of being employed ,as a, pump impeller. of the character formedby means of the mechanism shown anddescribed-herein. v i

Fig. 9 is a cross section of the generated. vane online99.ofFig.8. 7-.

Fig. 10 is a transverse-section of the mechanism on line 10-10 of Fig. 1. r I v, i

Fig. 11 is a fragmentary section of the same on line 11-11 of Fig. 1.

Fig. 12 is a fragmentary section on line 12-12 ofFig.-I0.-- Y .Fig. 13 isa diagram of a, vane generated ,by. means of my improved mechanism showing' a vane extended and illustrating the varying thickness thereof. 1

' Fig. 14 is a section of themechanism on line my invention includesa suitable bed A which is adjustably supported on a pedestal B and is adjustable relative to and additionally supported on the table C of a milling machine. The bed A serves as a support for a mechanism which is arranged to automatically move the work D relative to a cutter or tool E, Which is fixed in its position on and is operated by the milling machine. Said mechanism comprises a base 1 provided with longitudinally alined bearings 2 and 3 which rotatably support a spindle 4 on which the work D is fixedly held. The spindle 4 carries a worm gear 5 centrally of the bearings 2 and 3 and said gear meshes with and is rotated by means of a worm 6 which is mounted on a transverse shaft 7 journaled in bearings 8 and 9. The shaft 7 carries a worm gear 10 on one end thereof, which is operated by means of a Worm 11 on a drive shaft 12, which is journaled in longitudinally alined bearings 13 and 14 on the base 1 and disposed at one side of the fixture, as shown in Fig. 1.

A suitable sliding coupling 15 of well known form is provided for connecting the drive shaft 12 with the operating spindle of the milling machine, as at 16. The spindle 4 is provided with a pair of similar worms 17 and 18 arranged on opposite sides of the central gear 5 in operative connection with worm gears 19 and 20 respectively. The gears 19 and 20 are rotatably mounted in enlarged bearings, as at 21, formed on the base 1, and to that end the gears are hollow and provided with enlarged sleeves 22, which are rotatable within bushings 23 fixedly held in the bearings 21. Each of the gears is provided with a detachable flange 24 on its bottom, which has a bushed bore 25 therein forming a journal for a pin 26 by means of which said gears 19 and 20 are eccentrically mounted with respect to the bed A. (See particularly Figs. 1 and 10). The pin 26 has a flat transverse portion 27 below the plate 24 which is adjustable in a transverse slot 28 formed in the bed A, and said pin may be fixedly positioned in said slot by means of a nut 29 and a washer 30 on the lower side of the bed A.

The structure is typical of both of the gears 19 and 20, and the adjustment of said gears is uniform to the end that the axes of the pins 26 will be correspondingly spaced from the axes of the gears to provide a uniform degree of eccentricity. When the eccentricity of the gears is to be changed it is necessary to remove the plate 24 and substitute another plate therefor with the bore 25 differently positioned, and the slot 28 permits the differential positioning of the pins 26 to corresponding to the desired eccentricity of the gears.

In the operation of the fixture it will be obvious that while the gears rotate in the bearings 21 of the plate 1, the axes of the gears move in a circular path around the axes of the pins, and this movement of the gears eiTects a circular motion of the base 1 and all of the mechanism thereon around the axes of the pins 26. Thus the work D is moved in a circular path with respect to the cutter E.

The ratio of the gears 19 and 20 to their associated worms 17 and 18 respectively is the same, and in each case corresponds to the ratio between the number of teeth on the gate F in Figs. 17 and 18 and the vane G on the impeller.

The bed A is adjustably mounted on the table C of the milling machine by means of bolts 31 which are arranged in pairs or otherwise on opposite sides of the spindle 4 and extend thru arcuate slots 32 in the base 1. Said bolts carry nuts 33 on their upper ends which are seated in arcuate" depressions 34 in the bed A, and are secured to a plate 35 which is attached to the milling machine table C by means of bolts 36.

The bed A is pivotally mounted on the plate 35 by means of a member 3'7 which has an enlarged head 37 pivotally held in a corresponding bore of the bed and having a reduced extension 38 fixedly secured in the plate 35 by means of a set screw 39, or otherwise. The pivot pin 37 is centrally positioned relative to the cutter E and the slots 32 and 34 in the bed are concentrically formed relative to the axis of said pin so that the bed may be adjusted relative to the cutter E to correspond to the lead of the vane to be out. When so adjusted the bed is fixedly held in its proper relation to the cutter by means of the nuts 33 and bolts 31.

The pedestal B has a tubular column 40 extending upwardly from a base 41, which is adapted to support the pedestal on a floor adjacent a milling machine, and an internally threaded sleeve 41 is provided within the column 40 for adjustably receiving a vertical screw 43, whereby the head 44 of the column upon which the bed A rests may be vertically adjusted for raising and lowering the mechanism to a proper elevation relative to the milling machine. The screw 43 is provided above the column 40 with a transverse portion 45 having a bore 46 arranged to receive a. rod, whereby the screw may be rotated, and an extension 47 is provided above the portion 45 which is insertable in a bore 48 of a boss 49 depending from the head 44, as shown in Fig. 6.

The head 44 is provided with a pair of transversely alined rollers 56, 50 carried on pins or screws 51, 51 and rotatably engage the lower side of the bed A, as shown in Fig. 6, for rendering the movement of the bed on the pedestal frictionl less. The bottom of the bed is provided with an arcuate rail 52 which is secured to the bed by suitable means and is concentrically formed relative to the axis of the pin 37. Said rail rests upon a pair of grooved rollers 53, 53 rotatably supported on extensions 54, 54 from the head 44, as shown in Fig. 5.

Preferably the spindle 4 is arranged as shown in Fig. 6, with a tapered bore 55 in its front end arranged to receive and fixedly hold by suitable i."

means a mandrel 56, on which the work D is held, as shown or otherwise. The mandrel may be held against displacement in the spindle by means of an attaching rod 58 extending thru an axial bore in the spindle and held by means of a nut 59 at the rear end of the spindle. In Figs. 17 and 18 I have shown the gate F arranged with a plurality of teeth 60, 60 etc., spaced apart uniformly and extended at right angles toa web 61 so as to provide uniform spaces 62 between the teeth for receiving the vane 63 of the worm G.

It will be noted that the axis of the gate is offset from the axis of the worm and is at right angles thereto, and as illustrated in Fig. 17, the

pitch line of the teeth 60 is tangent to the perpen- I dicular plane of the axis of the worm. Thus the worm in its rotation engages the spaces 62 between the teeth and rotates the gate F. The teeth 62 are variable in their position relative tothe vanes 63, as clearly shown in the drawings, and

As the teeth are moved in one or the other directions from this: central positiomthe clearance for the vane decreases, and it: is therefore appar; ent that the-thickness of, the vane must;neces-; sarily be variable to correspond to the variation in the clearance between the 'teethduringthe rotation of the gate. Thus the minimum thickness would be at a distance remotest from, the central position stated, and the maximum thickness would be at central fposition.;- 1 y The teeth are providedwith arcuate edges so as to provide for efficient operationrand may beof the form shown, orin lieu of such form .the teeth may be perfectly round so as to. present rounded surfaces to and for contact with-the; sidesv of a vane at all times andthus reducentheiriction to a minimum.- i 5,

Asshown inyFig. 1 3, the vane 63,-is extended as if it had been removed from itsthub and; stretchedout into a straight section. -'I-heoreti cally, the vaneis thickest atapoi-nt central-be tweenthe two'ends 65 and:6 6, and is finished-at said ends.) 1

In the generation of the'vanethe opposite sides are cut inwardly from planes indicated by: broken lines. 6'7 and 68, while the continuingportions ofi said sides are theoretically parallel'and coincident with the lines 67 and 68, Thusthe necessity for this form of vane is illustrated clearly in.-Fig.'-;;17,- wherein-it is .quite apparent that the, central per: tion 64 of maximum thickness is shown inits-cem; tral position.withrespect-gtotwo of the teeth,60 of the gate, while the portions near the ends of the vane are substantially reduced to.ccrr espond to the actual clearance in ,the spaces 62011; oppo! side sides ofthe central; position.

In the form of device shown, the cross section of the vane 63 as illustrated in Fig. 9 is tapered with the maximum width of the vane at the root and the minimum width at the face. In order to cut a vane of such form as that shown, the cutter E may be arranged as shown in Figs. 2, 3 and 4, or otherwise.

Said cutter '70 has a plurality of detachable teeth 71 mounted therein which have tongues '72 adapted to slide in ways '7 3 and are held by wedges Mas shown in Fig. 3. This particular form of cutter, however, is not essential to the cutting of a worm of the form shown in Fig. 8.

When and if the cross section of the vane 63 v is rectangular, a different form of cutter from that shown is required, preferably a cutter with the cutting edges arranged parallel to the axis of the cutter and partaking somewhat of the form of an end mill. In such case it is apparent that a different form of cutter would be differently mounted in a milling machine from the cutter E shown.

In operation, the number of teeth in the gate F and the number and lead of the vane 64 in the worm G to be cut being first determined, the gears 19 and 20 and worms 17 and 18 are provided in ratios corresponding therewith so that the movement of the work relative to the cutter E will correspond exactly to the movement of the gate relative to the worm G. The bed A is then mounted on the milling machine table C and adjusted to correspond to the lead of the vane to be out, i. e., the work D is arranged at such an angle relative to the cutter E as will correspond with the lead to be established.

When the proper angle is obtained the bed is locked in position on the milling machine table by tightening the nuts 33 on the bolts 31. The driving spindle 12 is then operatively connected with the driving spindle 16 of the milling machine and the work D is fixedlyi-mounted-ronthegexg tended end of the mandrel.,56;..w.;-When power is applied to' the; mechanism the eccentricity of the gears '19 and 20- serves; to, rotate the bases-1 ;-and the mechanism thereon-and the =.work= D. as aunit relative to. the-cutter and the work .is simultane ously rotated on the axis ofthe shaft 4lwhilethecutter is also rotated-on itsraxis; "It-W111 beunderstood that the eccentric movemen of ears 191 11 2 szv ry limited 5.0513 Wh l the, cutte E st ave s nethe p r ph ry hcwq k :D 017 cutt t ne; ;t mechanism as aunit will rotate-in but aslight frac tion of a revolutionandjonly-sufiiciently to permit the generation of ,the vane in the work; to corresn n gteithe tra ers -ref .th t et .1 he. sa e .62. x th va -wwhenth rm. cut s opera-1 tively mounted in. a;pump or the;likes,

For, instance, referring. to..-Fig.,; .17 the-arc of movement of the assembled mechanism relative to the; cutter, E will correspond; .to, substantially three times the pitch distance between.the teeth 62.--of gate F, ;-assurning that. the; gate as? seenjin Fig. 17 is rotating inqayclockwisedirection More clearly explained, the length; of ;-safrd ,arc corresponds to the distance between the tooth fw n t o t 3.; sh wn n F 1 Thus' ne of; t e-te h 62.wQu d=-en .t va 63 ..from: n tia ion-as d ua ed.;-at1fizii hruout 5515 1 .o st axe ...unt iii-h s. r ach d, its final p iqn a men W i 2.1 r presente a 63.- The speedof the. mechanism isso regulated a t e u tenE w l mak acompl te. ut u in ts e sa mentizi ithe work D, n h vene.

3 W i 2 el 1f. &6 h QbY Willcorrespond. ex: actly in thickness to the requirements for close contact between the opposite sides of the vane and the corresponding edges of teeth 62.

What I claim is:

1. A device of the character described comprising a bed adjustable relative to a tool having a fixed axis of rotation, a base automatically adjustable on said bed relative to said tool during a cutting operation and including a spindle for operatively supporting the work in cutting engagement with said tool, and a pair of gears worm connected with said spindle rotatably mounted on said base and eccentrically fixed on said bed for gradually adjusting the work in an arcuate path relative to and during the rotation of said tool to correspond to the varying thickness of a vane to be cut on said work.

2. A device as characterized in claim 1 including a supporting member for said bed, means for pivotally connecting the bed with said supporting member at a point substantially alined with said work whereby the adjustment of the bed to selected fixed positions may be effected substantially about the axis of the work to correspond to the lead of the vane to be out.

3. A mechanism for generating a helical vane of varying thickness, comprising a supporting member, a bed adjustable thereon at a point substantially adjacent the axis of the work, means for fixedly supporting said bed in adjusted posi-' tions, a base adjustable on said bed, a spindle rotatable on said base and for supporting the work in cutting position relative to a tool, means for operatively connecting said spindle with a source of power, and gears worm connected with said spindle rotatably mounted on said base and eccentrically mounted on said bed for gradually adjusting said bed and said work'relative to said tool during a vane cutting operation, the ratio of said gears to said spindle corresponding to the ratio between a member adapted to be engaged with said vane and the vane.

4. A, mechanism for generating a helical vane of varying thickness, including an adjustable bed fixedly supported at a selected position relative to a cutting tool to correspond to the lead of the vane to be cut, a base adjustable on said bed, a spindle on said base for supporting the work in cutting engagement with said tool, and means on said base connected with said bed and with said spindle including a pair of worm connected eccentrically mounted gears for gradually adjusting the Work relative to said tool so as to vary the thickness of the vane-whereby the vane when out will closely mesh with the teeth of a gear as the angles of the teeth are changed relative to the vane, the ratio of said means with respect to said spindle exactly corresponding to the ratio between the cut vane and the gear to be meshed therewith.

5. A mechanism for generating a helical vane as characterized in claim 4, including means on said bed for varying said ratio whereby to cut vanes of different character.

6. A mechanism for generating a helical vane of varying thickness comprising a supporting member, a bed adjustable and fixedly held on said member relative to a cutter having a fixed axis of rotation, a base adjustable on said bed relative to said cutter, a spindle rotatable on said base for supporting the work in operative engagement with said cutter, said spindle including a pair of longitudinally spaced worms, a pair of light gears rotatable on said base and meshing with said worms, and means on said base eccentric with '7. A vane generating mechanism comprising a fixedly held bed adjustable relative to a cutting tool, a support for the work rotatable on the bed relative to said tool, gearing having a ratio to said work to correspond to the ratio of the cut vane to a gear to be operated thereby for automatically effecting a relative rotative adjustment between the tool and the work during the simultaneous rotation of the tool and the work about their respective axes, and a rotatable spindle for the work, said gearing including gears operatively connected with said spindle and rotatable about fixed axes on said bed which are eccentric to the axes of the gears.

8. A vane generating mechanism comprising a fixedly held bed adjustable relative to a cutting tool, a support for the work rotatable on the bed relative to said tool, gearing having a ratio to said work to correspond to the ratio of the cut vane to a gear to be operated thereby for automatically effecting a relative rotative adjustment between the tool and the work during the simultaneous rotation of the tool and the work about their respective axes, and a rotatable spindle for the work, said gearing including gears operatively connected with said spindle and rotatable about fixed axes on said bed which are eccentric to the axes of the gears, and means for adjusting the fixed axes of said gears on the bed to correspond to the variation in the cut to be made on the work.

LOREN G. SYMONS. 

